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spf=tempfail smtp.mailfrom=dm-devel-bounces@redhat.com Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-192-zaJZS1s1P8eFxfSIeBFzeg-1; Fri, 27 Nov 2020 10:51:51 -0500 X-MC-Unique: zaJZS1s1P8eFxfSIeBFzeg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E90B48030AE; Fri, 27 Nov 2020 15:51:46 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 680251002393; Fri, 27 Nov 2020 15:51:46 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 986AB18095C7; Fri, 27 Nov 2020 15:51:45 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 0ARFlJw5003926 for ; Fri, 27 Nov 2020 10:47:19 -0500 Received: by smtp.corp.redhat.com (Postfix) id A2A392026D47; Fri, 27 Nov 2020 15:47:19 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast03.extmail.prod.ext.rdu2.redhat.com [10.11.55.19]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9DD832026D5D for ; Fri, 27 Nov 2020 15:47:15 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5D7AA811E78 for ; Fri, 27 Nov 2020 15:47:15 +0000 (UTC) Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-519-gvEuh3SgPvO4hP_KpI7ZTQ-1; Fri, 27 Nov 2020 10:47:12 -0500 X-MC-Unique: gvEuh3SgPvO4hP_KpI7ZTQ-1 Received: by verein.lst.de (Postfix, from userid 2407) id C6DB768B05; Fri, 27 Nov 2020 16:47:09 +0100 (CET) Date: Fri, 27 Nov 2020 16:47:09 +0100 From: Christoph Hellwig To: Jan Kara Message-ID: <20201127154709.GA8881@lst.de> References: <20201126130422.92945-1-hch@lst.de> <20201126130422.92945-44-hch@lst.de> <20201127131901.GE27162@quack2.suse.cz> MIME-Version: 1.0 In-Reply-To: <20201127131901.GE27162@quack2.suse.cz> User-Agent: Mutt/1.5.17 (2007-11-01) X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-loop: dm-devel@redhat.com Cc: Jens Axboe , Mike Snitzer , linux-mm@kvack.org, Greg Kroah-Hartman , Jan Kara , Josef Bacik , Coly Li , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, dm-devel@redhat.com, linux-mtd@lists.infradead.org, Johannes Thumshirn , Tejun Heo , linux-bcache@vger.kernel.org, Christoph Hellwig Subject: Re: [dm-devel] [PATCH 43/44] block: merge struct block_device and struct hd_struct X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Fri, Nov 27, 2020 at 02:19:01PM +0100, Jan Kara wrote: > The percpu refcount is long gone after the series refactoring... True. > > @@ -939,13 +910,13 @@ void blk_request_module(dev_t devt) > > */ > > struct block_device *bdget_disk(struct gendisk *disk, int partno) > > { > > - struct hd_struct *part; > > struct block_device *bdev = NULL; > > > > - part = disk_get_part(disk, partno); > > - if (part) > > - bdev = bdget_part(part); > > - disk_put_part(part); > > + rcu_read_lock(); > > + bdev = __disk_get_part(disk, partno); > > + if (bdev) > > + bdgrab(bdev); > > Again I think you need to accommodate for bdgrab() returning NULL here when > we race with partition destruction... For that we need to allow bdgrab to return NULL first, but otherwise this seems like the right way. -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BC45FC6379D for ; Fri, 27 Nov 2020 15:47:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88CA721D7A for ; Fri, 27 Nov 2020 15:47:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731137AbgK0PrO (ORCPT ); Fri, 27 Nov 2020 10:47:14 -0500 Received: from verein.lst.de ([213.95.11.211]:37960 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730324AbgK0PrN (ORCPT ); Fri, 27 Nov 2020 10:47:13 -0500 Received: by verein.lst.de (Postfix, from userid 2407) id C6DB768B05; Fri, 27 Nov 2020 16:47:09 +0100 (CET) Date: Fri, 27 Nov 2020 16:47:09 +0100 From: Christoph Hellwig To: Jan Kara Cc: Christoph Hellwig , Jens Axboe , Tejun Heo , Josef Bacik , Coly Li , Mike Snitzer , Greg Kroah-Hartman , Johannes Thumshirn , dm-devel@redhat.com, Jan Kara , linux-block@vger.kernel.org, linux-bcache@vger.kernel.org, linux-mtd@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 43/44] block: merge struct block_device and struct hd_struct Message-ID: <20201127154709.GA8881@lst.de> References: <20201126130422.92945-1-hch@lst.de> <20201126130422.92945-44-hch@lst.de> <20201127131901.GE27162@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201127131901.GE27162@quack2.suse.cz> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-bcache@vger.kernel.org On Fri, Nov 27, 2020 at 02:19:01PM +0100, Jan Kara wrote: > The percpu refcount is long gone after the series refactoring... True. > > @@ -939,13 +910,13 @@ void blk_request_module(dev_t devt) > > */ > > struct block_device *bdget_disk(struct gendisk *disk, int partno) > > { > > - struct hd_struct *part; > > struct block_device *bdev = NULL; > > > > - part = disk_get_part(disk, partno); > > - if (part) > > - bdev = bdget_part(part); > > - disk_put_part(part); > > + rcu_read_lock(); > > + bdev = __disk_get_part(disk, partno); > > + if (bdev) > > + bdgrab(bdev); > > Again I think you need to accommodate for bdgrab() returning NULL here when > we race with partition destruction... For that we need to allow bdgrab to return NULL first, but otherwise this seems like the right way. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 25F5DC2D0E4 for ; Fri, 27 Nov 2020 15:48:11 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A35FC21D7A for ; Fri, 27 Nov 2020 15:48:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="0Nli6qq0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A35FC21D7A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=mWWjlImr+lLgeJ4pOdOP0UqEbuTF95VHOo3Q9jWrJLU=; b=0Nli6qq0xBBttLsDqOV4SsNgO Or9r5gu+8KPACpzxovjWzp32syjZv+VnjhM0ZhgB5LK1ipBPXCChZJuDfHl+obCkPwiruedBnngYu byR5DqD/bfkYVV+P6JkuNoIMNUDQeTaY0iq6vDjaiiB5INNhTtN9HlmnadhTSN75cyOTCIc+yjcyX NAuEnKRJYL4LZWWcfQLlVvpJ8cSNWi675JCk/cePWr4/P/KyrlpEiBfYbnAck7pxVmOT6M9+zb8aJ l45h6JKvUgu5TK9MzR+VBpCJtZb6Odf3HxMgHUT72Q18hpyKqpOpnTQS6YArPDsR5u+WcqQKY+oJo Wr2zNjTFg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kifxr-0006eb-6d; Fri, 27 Nov 2020 15:47:15 +0000 Received: from verein.lst.de ([213.95.11.211]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kifxo-0006Ov-KM for linux-mtd@lists.infradead.org; Fri, 27 Nov 2020 15:47:13 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id C6DB768B05; Fri, 27 Nov 2020 16:47:09 +0100 (CET) Date: Fri, 27 Nov 2020 16:47:09 +0100 From: Christoph Hellwig To: Jan Kara Subject: Re: [PATCH 43/44] block: merge struct block_device and struct hd_struct Message-ID: <20201127154709.GA8881@lst.de> References: <20201126130422.92945-1-hch@lst.de> <20201126130422.92945-44-hch@lst.de> <20201127131901.GE27162@quack2.suse.cz> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201127131901.GE27162@quack2.suse.cz> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201127_104712_820699_983CF375 X-CRM114-Status: GOOD ( 13.07 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jens Axboe , Mike Snitzer , linux-mm@kvack.org, Greg Kroah-Hartman , Jan Kara , Josef Bacik , Coly Li , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, dm-devel@redhat.com, linux-mtd@lists.infradead.org, Johannes Thumshirn , Tejun Heo , linux-bcache@vger.kernel.org, Christoph Hellwig Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Fri, Nov 27, 2020 at 02:19:01PM +0100, Jan Kara wrote: > The percpu refcount is long gone after the series refactoring... True. > > @@ -939,13 +910,13 @@ void blk_request_module(dev_t devt) > > */ > > struct block_device *bdget_disk(struct gendisk *disk, int partno) > > { > > - struct hd_struct *part; > > struct block_device *bdev = NULL; > > > > - part = disk_get_part(disk, partno); > > - if (part) > > - bdev = bdget_part(part); > > - disk_put_part(part); > > + rcu_read_lock(); > > + bdev = __disk_get_part(disk, partno); > > + if (bdev) > > + bdgrab(bdev); > > Again I think you need to accommodate for bdgrab() returning NULL here when > we race with partition destruction... For that we need to allow bdgrab to return NULL first, but otherwise this seems like the right way. ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/